Combined sintering and stretching process.



K. R. R. SEIFERT.

COMBINED SINTERING AND STRETGHING PROCESS.

APPLICATION FILED APB..21, 1913.

Patented July 14, 1914.

E. E'. sEIFER'L'oF CHARLOTTENBUEG, GERMANY.'

COMBINED SINTERING Ann STRETCHING PaooEss'.

Specication of Letters Pate-nt.

Patented July 14, 1914.

Applieation mee April 21;, 1913. seriai N0. 762,4s4.

To all whom it may concern.'

Be it known that I, KARL R. R. SEIFERT, a citizen of the German Empire, and a resident of Charlottenburg, Berlin, Germany,

have invented certain new and useful Improvements in Combined Sintering and Stretching Processes, of which the following is a specification.

This invention relates to a method of and apparatus for the combined sintering and vstretching of Wolfram, titanium, tantalum,l uranium and other metals and their alloys having ahigh fusion point. The object of the invention is to devise a process in which the said metals or their. alloys may be sintered and stretched by means of an electric current.

Another object of the invention is to pro-` vide an apparatus for the carrying out of the process.

Before being sintered and` stretched the crystals or finely divided particles of the metal or` alloy have been compressed or otherwise formed into rods or ingots of suitable size preparatory to their Afurther treatment, which heretofore have involved the use of a great deal of machinery such as electric furnaces, swaging, hammering, and rolling machines before being acted upon by the well known wire drawing machinery which produces Ythe line wires for filaments, resistances or other uses. The known manner of t-reating the metals 'or their alloys necessarily involves a great deal of time and expense and causes considerable waste.

The object of my invention, as stated above, is to provide a single apparatus in which the combined process of sintering an'd stretching may be carried out in a simple andi practical manner and with little expenditure of time and labor and at a comparatively low cost.

The invention is embodied in an apparatus for carrying out the process and which is l5 described in, detail in the following speciication while reference is had to the a'ccompanying drawing, which is to be under l stood as illustrating the preferred form of the apparatus but vnot as showing the only "0 form in which my invention may be emtional view of an apparatus for carrying out my process 'of combined vsmterlng and 5 stretching. F1g. 21s a. detail view-illus? trat-ing a step in the process. Fig. 3 is a detail view of ya water cooled die used, in the apparatus and Fig. 4' illustrates the process diagrammatically.

Referring to the drawing the referenceV numeral 5 representsa suitablebase for the machine and in which is secured adie support` 6. The die support Gis provided with a socket 7 into which islaid a die holder 8 'through the opening 9, The die holder. e5 contains the die frame 11 in which is supported a die 12,of suitable, material, such as a'hard stone for instance, or-as shown in Fig. 3, I may prefer a hollow hard steel die provided w1th means as 51 for watercoola0 ing. 1 3. is the opening in the die. The aforesaid parts are preferably cylindrical and the die frame 11 is removably held in the die holder to facilitate the exchange of dies as will be pointed out later. Into the die support 6 there are screwedl pipes -14 and 15 generally v of metal, and these pipes are lined with lsleeves 16 o f insulating material. End pieces or holding means 17 of insulating material are sccuredfo at the outer ends of the pipes ,14 and 1 5. and- A provided with apertures forming bearings or guiding means 1S' for ,the electrodes 19 -and 20 to which current `is supplied by means of cables 21 :secured to.' clampingn35 `means 22k of ,conducting material and clamped to the said electrodes as shown.

The electrodes are movable lengthwise with.-

;in the sleeves 16 through the bearings4 18.

If desired, other suitable guiding means may be provided. l.

T-he electrpdes 19 and 20 consist of hollow pipes of sultable material such as copper for instance and are provided wi'thuneans for securing the metal ingot between them. g5

AIn the drawing such means are illustrated and may comprise for the elect-rode 19 a pair of jaws 23 pivoted to a conducting holder 24 secured in the end of the electrode.

25 is a sleeve which may be moved to causeloo the jaws to close as will be understood.

A holder 2 6 is provided inlthe lelectrode- 20. The holder has a conical head 27 or other means forcausing the jaws 28 to close by xpanding them on one side of their 105 pivot 29. 4*In `the drawing, Figure 1 is a vertical secf The electrodes are hollow and. water cooled. Water is admitted through the pipes 30 into the interior of the electrodes and passes out through the Ypipes 31. Suitable 4110 Stated briefly, the operationVV consists inv securing the ingot of the met-al between the electrodes, heating the ingot to cause it to Vsinter and 'drawing the ingot through-the die to stretch it.I The ingots have a' diameter of about 8 mm.,a1id are stretched to a diameter of about 1 mm., these dimensions, however, not being absolute or controlling. j Describing the 'process in detail, the ingot 40 isshaped at one end so as to .pass through a die having a die opening of less diameter than the ingot which is gripped by the jaws 28 as seen in Fig. 2. The other end of thel ingot is caught between the jaws 23 and the sleeve 25 is moved out over the jaws to secure the ingot. Then the current is turned on and passes through the electrodes and the ingot 40, thus heating 'the latter. At the same time water is admitted to the electrodes to cool them and reducing gases are admitted through the pipes 32 to prevent oxidation of the ingot during the process. A current of about 1000 to 1500 amperes, more or less depending upon the fusibility of the metal and the dimensions thereof, is sent through the ingot and causes it to sinter by the action of the heat and simultaneously therewith the stretching process commences by pulling on the cable 38 by suitable means to draw the .hot ingot through the die and whereby the ingot is Jreduced in diameter.

.The harder the pull onx the electrode 20, the

harder the ingot is clamped between thejaws 28 because of the cone-shaped head 27. As the electrode moves out throughA the bearing 18 the ingot is stretched through the die and the pulling power will be transmitted to the electrode 19 which will move. to the right also until the sleeve 25 abuts the die holder. Continued pull frees. the jaws 23 from the sleeve and the metal will be stretched and drawn through the die and the current will be automatically broken. Thereafter the apparatus is taken apart, a .die having a smaller die opening is inserted, the ingot is again secured to the electrodes, a current of sufficient amperage is sent through the ingot to heat and further sinter it and the ingot is again vthe apparatus is taken apart, a still smaller die is inserted, the ingot, which gradually has assumed the shape of a rod, is again heated by a proportionately reduced current and stretched, and. so the operation is repeated until the rod ofmetal has been reduced to a diameter of about 1 mm. more or less. I

The process of reducing the ingot by sin-L -further reduced to arod 63, by

stretched through a die 64 having. a smaller Then tering 'and stretching through the repeated l operation as described is shown diagram-1.

Amatically in Fig. 4, in which an ingot 60l is shown as having been reduced to a rod 61 by heatingandgpassing it through a die 70 62; andthe rod 61is shown as beingO still Memg opening than the-die 62, and the rod 63 is shown finally" reduced to a very thin'rod 75 by being stretched througha die 660i` less die opening thanA the die-.6 4L.-

Fig. 4 does noti-llustrate the entireoperation or process, but only three stagesthereing the rod through theva'rious sized dies is repeated as `often as isnecessary .until a rod of the required thinness has beenobtained.

Further, it will be .understood andis a feaof. The operation of -sintering and stretch- 30 tureJ of my invention, that with each reduction in diameter of the metal, the current is correspondingly reduced. Also,- that I may at each stage of the process either heat the metal to sinter it and simultaneously therewith stretch the metal, or I may at certain '90 shown finally reduced to a very thin rod 65 by being stretched through a die 6 of less die opening than the die 64.

From the foregoing it will be seen that my invention provides' a process whereby an -ingot or rod of metal is reduced in diameter from one given dimension to another given dimension by a combined process of sintering and stretching, by means of an electric current and by repetitions of the process, in which each stage is lsimilar to another stage except that the amperage of the current is proportionately reduced as the metal is reduced in diameter by passing it through the dies of varying die openings. l

It will be seen. that the apparatus described is of very simple construction and easily operated. The pipes 14 and 15 which form a sintering chamber Qare quickly detached from thedie support 6 by unscrewing the pipes and the dies may readily be changed as they'a-re removably held `-in the die frame as shown.

The form of the apparatus as illustrated is susceptible of changes within the principle of invention and I do not wish to limit" myself otherwise than as demanded by the scope `of theappended claims. I claim :I 9

l. The method of sintering and stretching` wolf-ram or other metals and their `alloys `which consists in sintering the metal by means of an electric current,y stretching the ics lio

metal by passing it-through a suitable die means of an electric current and simultaneously therewith stretching the metal by passing it through a suitable water cooled die.

3. The method of sintering and stretching Wolfram .or other metals and their alloys which consists in sintering the metal by means of an electric current and simultaneously therewith stretching the metal by passing it through a suitable water cooled die,

I:and subjecting the metal during the sintering and stretching process to the influence of reducing gases.

4. The method ofsintering and stretching Wolfram or other metals and their alloys which consists in subjecting the metal to the action of an electric current to sinter it and simultaneously therewith treating the metal mechanically 'to stretch it.

'5. The method of sinterng and stretching Wolfram or other metals and their alloys which consists in passing'an electric current through .the metal to sinter it and stretching the metal by passing it through a suitable die while the current is on.

6. The method of sinteringand stretching Wolfram or other metals and their alloys which consists in heating the metal to sinter 'it and simultaneously therewith reducing the diameter of the metal by mechanical means.

7. The method of sintering and stretching Wolfram or other metals and their alloys4 which consists in securing the metal between two electrodes,sintering the metal by pass! ing a continuous electric current through it and the electrodes and operating the latter to stretch the metal simultaneously with the sintering thereof.

8. The method ofl sintering and stretching wolframor other metals and their alloys which consists Qin passing one end of the metal 'through adie, securing the metal be.- tween two electrodes, one on each side of said die, sintering the metal by passing an electric current through it and .simultaneously therewith stretching the metal by passing it through .the said die.

9. The method of sintering and stretching Wolfram or other metals and their alloys which 4consists in heating the metal to sinter it, stretchingthe metal by passing it through a mechanical reducing means while maintaining the heat and subjecting the material to the influence of reducing gases during the entire process.w

10. An apparatus for the combined sinterin g and stretching of Wolfram or other metals and their alloys comprising two 'electrodes, means for securing the metal or alloy between the same, means for passing an electric current through said electrodes and the metal or alloy, a die and means for mechanically operating said electrodes to tretch the metal or alloy through the said 11. An apparatus for the combined sintering and stretching of Wolfram or other metals and their alloys comprising two electrodes, means for securing the metal or alloy between the electrodes, a die, means for operating the electrodes to stretch the metal through the said die and means for passing continuous electric current through the metal or alloy while the same is being stretched.

12. Arf apparatus for the combined sintering and stretching of Wolfram or other metals and their alloys comprising a cylinder, a die in the same, two electrodes supported one on each side of said die, means for securing the metal or alloy between said electrodes, means for passing an electric current through said electrodes and metal or falloy, means for operating the electrodes to stretch the metal or alloy through the die, means for cooling the electrodes and means for admitting reducing gases to said cylinder.

13. An apparatus for the combined sintering and stretching of Wolfram or other metals and their alloys comprising a support, a die removably held in said support, cylinders removably secured to the latter to both sides of said die, end pieces secured to the outer ends of said cylinders, electrodes movably supported in said end pieces, means for passing an electric current through said electrodes, means for cooling the latter and means for admitting reducing gases to the said cylinders. y 14. An apparatus for the combined sintering and stretching of Wolfram or other metals and their alloys comprising a center support, a die in the same, pipes removably secured to said support to form cylinders to both sides of the die, an electrode movably supported in each cylinder, means at the inner ends of the electrodes for securing the metal or alloy between them, means at the outer ends of the electrodes for passing an electric current through them and mechanism connected to one of said electrodes for operating the electrode lengthwise of the cylinder in which the electrode is supported.

Signed at New York, N. Y. this 17th day of April 1913.

KARLV R. R. SEIFERT.

Witnesses:

K. G. LEARD, HERMAN LUDWIG GYNE. 

